I am currently unsuccessful at being prompt to add a char for my current program. I am able to add a digit but it will post the prompt to add a character but skips to input portion and directly asks me if I want to continue.
#include <stdio.h>
#include <malloc.h>
#include <stdlib.h>
main()
{
struct node
{
int num;
char gender[3];
struct node *ptr;
};
typedef struct node NODE;
NODE *head, *first, *temp = 0;
int count = 0;
int choice = 1;
first = 0;
while (choice)
{
head = (NODE *)malloc(sizeof(NODE));
printf("Enter the Student Identification Number\n");
scanf("%d", &head-> num);
printf("Enter the Student gender (M)or(F)\n");
scanf("%c", &head-> gender);
if (first != 0)
{
temp->ptr = head;
temp = head;
}else
{
first = temp = head;
}
fflush(stdin);
printf("Would you like to do another entry(Type No(0) or Yes(1))?\n");
scanf("%d", &choice);
}
temp->ptr = 0;
/* reset temp to the beginning */
temp = first;
printf("\nStudent Information\n");
while (temp != 0)
{
printf("Student ID number: %d\n", temp->num);
printf("Student gender: %c\n", temp->gender);
count++;
temp = temp -> ptr;
}
printf("No. of Students inputted into system: %d\n", count);
}
Related
After creating a hash table and assigning each letter to a value for the table, i am noticing the first word output by the table for the beginning of every linked list is the same word. Somehow it seems I am transferring the entire dictionary to each array in the table even though I have attempted to separate them. Any assistance would be awesome! Thanks in advance
// Implements a dictionary's functionality
#include <stdbool.h>
#include <stdio.h>
#include <stdlib.h>
#include <ctype.h>
#include <string.h>
#include "dictionary.h"
// Represents a node in a hash table
typedef struct node
{
char *word;
struct node *next;
}
node;
// Number of buckets in hash table
const unsigned int N = 25;
// Hash table
node *table[N];
char lowerword[LENGTH+1];
// Returns true if word is in dictionary else false
bool check(const char *word)
{
int bucketfind = 0;
int x = 0;
for (int b = word[x]; b != '\0';b = word[x], x++)
{
int lowertemp = tolower(word[x]);
if (x == 0)
{
bucketfind = lowertemp - 97;
}
char lowerfinal = lowertemp;
lowerword[x] = lowerfinal;
//printf("%c", lowerword[x]);
}
int wordlen = x + 1;
int pr = 0;
while (table[bucketfind] -> next != NULL)
{
int dwlen = strlen(table[bucketfind]-> word);
pr++;
//printf("%i, %i, %s, %i\n", pr, dwlen, table[bucketfind] -> word, bucketfind);
}
//TODO
return false;
}
// Hashes word to a number
unsigned int hash(const char *word)
{
int asciifirst = word[0];
int lowerfirst = tolower(asciifirst);
int bucketnum = lowerfirst - 97;
return bucketnum;
}
// Loads dictionary into memory, returning true if successful else false
int dictwords = 0;
//char *cword = (char*)malloc(sizeof(char)*46);
bool load(const char *dictionary)
{
char *cword = malloc(sizeof(char)*46);
FILE *dict = fopen(dictionary, "r");
if (dictionary == NULL)
{
return false;
}
int x = 0;
while ((fscanf(dict, "%s", cword) != EOF))
{
node *nword = malloc(sizeof(node));
nword -> word = cword;
nword -> next = NULL;
int bucket = hash(cword);
//printf("%i\n", bucket);
if (table[bucket] != NULL)
{
nword -> next = table[bucket];
table[bucket] = nword;
}
else
{
table[bucket]= nword;
}
dictwords++;
}
fclose(dict);
return true;
}
// Returns number of words in dictionary if loaded else 0 if not yet loaded
unsigned int size(void)
{
return dictwords;
}
// Unloads dictionary from memory, returning true if successful else false
bool unload(void)
{
// TODO
return false;
}
It's not just the first word; every word in the linked list is the same word (the last one read). cword gets 46 bytes of memory at a specific address here char *cword = malloc(sizeof(char)*46);. Every word from dictionary is read into that same address.
I want to make tree command in xv6, if you don't know the tree is to list out directories on the terminal. I know this is probably easy for you but the code is so far
#include "types.h"
#include "stat.h"
#include "user.h"
#include "fcntl.h"
#include "fs.h"
#include "file.h"
int
main(int argc, char *argv[])
{
if(argc < 2){
printf(2, "Usage: tree [path]...\n");
exit();
}
tree(argv[1]);
int fd = open(argv[1],O_RDONLY);
if(fd<0)
return -1;
struct dirent dir;
while(read(fd,&dir,sizeof(dir))!=0){
printf(1,"|_ %d,%d",dir.name,dir.inum);
//struct stat *st;
struct inode ip;
ip= getinode(dir.inum);
if(ip.type==T_DIR){
int i;
for(i=0;i<NDIRECT;i++ ){
uint add=ip.addrs[i];
printf(1,"%d",add);
}
}
}
return 0;
}
and it has been giving me numerous error on the terminal the first being file.h:17:20: error: field ‘lock’ has incomplete type
struct sleeplock lock; // protects everything below here
^~~~
I'm searching for sleeplock and there is nothing like that in the code. What is wrong with the code? Thank you for your help
You cannot use kernel headers (like file.h) in a user code. To use kernel functionnalities in your code, you must use system calls.
To achieve what you want, you could start from ls function and make it recursive.
One example made quickly:
I added a parameter to the ls function to display the depth of crawling
and call itself on each directory elements but two first which are . and ..
void
ls(char *path, int decal)
{
char buf[512], *p;
int fd, i, skip = 2;
struct dirent de;
struct stat st;
if((fd = open(path, 0)) < 0){
printf(2, "tree: cannot open %s\n", path);
return;
}
if(fstat(fd, &st) < 0){
printf(2, "tree: cannot stat %s\n", path);
close(fd);
return;
}
switch(st.type){
case T_FILE:
for (i = 0; i < decal; i++)
printf(1, " ");
printf(1, "%s %d %d %d\n", fmtname(path), st.type, st.ino, st.size);
break;
case T_DIR:
if(strlen(path) + 1 + DIRSIZ + 1 > sizeof buf){
printf(1, "tree: path too long\n");
break;
}
strcpy(buf, path);
p = buf+strlen(buf);
*p++ = '/';
while(read(fd, &de, sizeof(de)) == sizeof(de)){
if(de.inum == 0)
continue;
memmove(p, de.name, DIRSIZ);
p[DIRSIZ] = 0;
if(stat(buf, &st) < 0){
printf(1, "tree: cannot stat %s\n", buf);
continue;
}
for (i = 0; i < decal; i++)
printf(1, " ");
printf(1, "%s %d %d %d\n", fmtname(buf), st.type, st.ino, st.size);
if (skip)
skip--;
else
ls(buf, decal+1);
}
break;
}
close(fd);
}
#include<stdio.h>
main()
{char *names[4];
int i,a;
printf("ënter the guests names\n");
for(i=0;i<=3;i++)
{
scanf("%s",names[i]);
}
char *yourname;
printf("\nenter your name ");
scanf("%c",yourname);
for(i=0;i<=3;i++)
{a=strcmp(names[i],yourname);
if(a==0)
printf("\nwelcome");
break;
}
if(a!=0)
printf("\naccess denied");
return 0;
}
this is a program to check your entry in a show. first we give permitted names & then it asks your name ,it compares your name with the names in the guest list.
i m getting runtime error, plz tell me the correction.i want to use pointers to string so plz suggest correction in the existing program
when i run this program in devc++ after entering first name it gives program.exe stopped working.
The code will be like this:
#include <stdio.h>
#include <string.h>
#include <stdlib.h>
int main()
{
char *names[4];
int i,a;
printf("ënter the guests names\n");
for(i=0;i<=3;i++) {
names[i] = (char*) malloc(100 * sizeof(char));
scanf("%s", names[i]);
}
char yourname[100];
printf("\nenter your name ");
scanf("%s",yourname);
for(i=0;i<=3;i++) {
a = strcmp(names[i], yourname);
if (a == 0) break;
}
if (a==0)
printf("\nwelcome");
else printf("\naccess denied");
for(i=0;i<=3;i++)
free(names[i]);
return 0;
}
Your code have to be formated so we can give you a better answer.
Now, use gets to take your input, verify the guest match with your name inside the for loop, stop the loop when a match is found.
#include<stdio.h>
#include<string.h>
int main()
{
char names[4][20];
int i = 0;
int a = 0;
printf("Enter guests names: \n");
for(i=0; i<3; i++)
{
gets(names[i]);
}
char yourname[20];
printf("\n Enter your name ");
gets(yourname);
printf("\n Verify access right:");
for(i=0; i<3; i++)
{
a=strcmp(names[i], yourname);
if(a==0)
{
printf("\n welcome");
break;
}
else
{
printf("\n access denied");
}
}
return 0;
}
Although this looks like a homework assignment.
I was trying to come up with a program that will use a linked list to read data off a file and delete grades that are under 50%. I came up with this code but it gives me the error "type float' argument given todelete', expected pointer". Please help if you can.
#include<stdio.h>
#include<stdlib.h>
#include<conio.h>
#include<string.h>
struct node
{
int id;
char name[10];
float grade;
struct node * next;
};
void build_link(struct node * ap);
void happy (struct node * bp);
void delete_fail (struct node *np);
int main(int argc, char *argv[])
{
struct node head;
head.next = NULL;
build_link( &head);
happy(head.next);
delete_fail (head.next);
system("PAUSE");
return 0;
}
void build_link(struct node * tmp)
{
int nu_id;
char nu_nam[10];
float nu_grade;
struct node * np;
FILE *fp;
fp = fopen("Student.txt","r");
while (fscanf( fp,"%d %s %f", &nu_id, nu_nam, &nu_grade ) != EOF)
{
np = (struct node *) malloc ( sizeof (struct node) );
strcpy (np->name,nu_nam);
np->id = nu_id;
np->grade = nu_grade;
np->next = NULL;
tmp->next = np;
tmp = tmp->next;
}
}
void happy(struct node *np)
{
while (np != NULL)
{
printf(" %d %s %f \n", np->id, np->name, np->grade);
np = np->next;
}
}
void delete_fail(struct node* grade)
{
node *np;
if(np == NULL)
printf("\nElement not found");
else
{
This is where my problem lies. I am not sure how to fix this part right here.
if( np->grade <50 )
np->grade = delete(np->grade);**
else
if(np->grade > 60)
np->grade = np->grade;
}
}
I'm making a Remote Filesystem Server for my university and I'm having some trouble with reading the root directory... Here's the thing:
I've read the root inode (inode 2) and it has consistent data, I mean that, for example, owner user Id field is set at '1000'. Then I proceed to read the contents of the inode data blocks, but when I try to access to the data block in question (the only one that is addressed in the inode i_block array, 240 on my debugging) all bytes are set to '0'. Can anyone help me with this? It's really important. Note: I cannot make it another way than with mapped memory and I'm not opening a real disk, but rather opening a .disk linux file. It has been created with the command-line
mkfs.ext2 -F -r 0 -b 1024 ext2.disk 30000
Here's my code:
#include <linux/ext2_fs.h>
typedef struct s_inode *pinode; /* Pointer to inode struct */
typedef struct s_direct *pdir; /* Pointer to direct struct */
int main(int argv, char *argc[]){
int *data;
pdir root = malloc(sizeof(struct s_direct));
/* Code for mpping .disk file, fetching supernode, and other ext2 data */
/* fsys is a global variable that holds general ext2 system data */
fsys->root = get_inode(2);
data = get_cont(fsys->root);
root = (pdir)getblock(data[0]);
}
pinode get_inode(int idx){
pinode inod;
int grp, offs;
grp = (idx-1)/fsys->superblock->s_inodes_per_group;
offs = (idx-1)%fsys->superblock->s_inodes_per_group;
inod = (pinode)&fsys->diskmap[(fsys->group[grp]->itab)+offs*sizeof(struct s_inode)];
return inod;
}
int *get_cont(pinode inod){
int *cont;
int *idx;
int i=0;
int *block;
idx = malloc(sizeof(int));
cont = malloc(sizeof(int));
while(i < inod->i_blocks && i<13) {
realloc(cont, i*sizeof(int));
cont[i]=inod->i_block[i];
i++;
}
if(i < inod->i_blocks){
*idx=13;
block=(int*)getblock(inod->i_block[*idx]);
fetchcont(block, idx, cont, inod->i_blocks, 0);
}
if(i < inod->i_blocks){
block=(int*)getblock(inod->i_block[*idx]);
fetchcont(block, idx, cont, inod->i_blocks, 1);
}
if(i < inod->i_blocks){
block=(int*)getblock(inod->i_block[*idx]);
fetchcont(block, idx, cont, inod->i_blocks, 2);
}
return cont;
}
int fetchcont(int *block, int *idx, int *cont, int lim, int lvl){
int i=0;
if(lvl == 0){
while((*idx) < lim && i<fsys->bsize){
realloc(cont, (*idx)*sizeof(int));
cont[*idx]=block[i];
(*idx)++;
i++;
}
if(i>=fsys->bsize){
return 1;
}else{
return 0;
}
}else{
lvl--;
while(i<fsys->bsize){
if(!fetchcont((int*)getblock(block[i]), idx, cont, lim, lvl)){
return 0;
}
i++;
}
}
}
void *getblock(int idx){
char *block;
int grp, offs;
grp = (idx-1)/fsys->superblock->s_blocks_per_group;
offs = (idx-1)%fsys->superblock->s_blocks_per_group;
block = &fsys->diskmap[fsys->group[grp]->blocks+offs*fsys->bsize];
return block;
}
Solved the problem. I assumed that block n was the n data block, but the offset included ALL the blocks. I've changed my getblock function to
void *getblock(int idx){
return &fsys->diskmap[fsys->bsize*idx];
}
and worked!